Selectable velocity-based or position-based work vehicle operator control system

ABSTRACT

A control system is provided for a work vehicle having one or more actuation devices. The control system includes an operator input device configured to receive operator input from an operator of the work vehicle and a controller operatively connected to the operator input device and to the one or more actuation devices. The controller is configured to: receive a control mode selection input including a position control mode selection input or a velocity control mode selection input; receive an actuation request input from the operator input device; determine an operating command corresponding to the actuation request input from the operator input device according to the control mode selection input; and issue the operating command to the one or more actuation devices based on the position or velocity control mode.

STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE DISCLOSURE

This disclosure generally relates to work vehicles, and morespecifically to operator control systems of work vehicles.

BACKGROUND OF THE DISCLOSURE

Heavy equipment operators often operate large work vehicles using anoperator control system with a variety of operator control devices. Suchdevices may include joysticks, dials, buttons, switches, wheels, pedals,and the like. In complex vehicles, such as motor graders or wheelloaders, the operator may be required to manipulate a large number ofoperator control devices in succession or simultaneously to operatenumerous independent or interdependent sub-systems of the vehicle,including a steering system for directing the heading rate and directionof the vehicle, as well as systems that operate the tools or implementscarried by the vehicle.

Effective and efficient operation of the vehicle and its implements mayrequire the operator to perform intricate hand and arm gestures in orderto manipulate the control devices required to actuate these systemstimely and accurately. Such effective and efficient operation may becomplicated by operator control strategies that differ from vehicle tovehicle and/or from manufacturer to manufacturer.

SUMMARY OF THE DISCLOSURE

The disclosure provides a control system for a work vehicle that enablesthe operator to selectively operate under a position-based controlstrategy or velocity-based control strategy for operating an actuationdevice on the work vehicle.

The disclosure provides a control system for a work vehicle thatincludes one or more actuation devices. The control system includes anoperator input device configured to receive operator input from anoperator of the work vehicle and a controller operatively connected tothe operator input device and to the one or more actuation devices. Thecontroller is configured to: receive a control mode selection inputincluding a position control mode selection input or a velocity controlmode selection input; receive an actuation request input from theoperator input device; determine an operating command corresponding tothe actuation request input from the operator input device according tothe control mode selection input; and issue the operating command to theone or more actuation devices.

In one aspect, the disclosure provides a control system for a workvehicle having one or more actuation devices. The control systemincludes an operator input device configured to receive operator inputfrom an operator of the work vehicle and a controller operativelyconnected to the operator input device and to the one or more actuationdevices. The controller is configured to: receive a control modeselection input including a mode selection input as a position controlmode or a velocity control mode; receive an actuation request input fromthe operator input device; determine an operating command correspondingto the actuation request input from the operator input device accordingto the control mode selection input; and issue the operating command tothe one or more actuation devices. In the position control mode, theoperating command includes an instruction to move the one or moreactuation devices to a position corresponding to a positioncorresponding to the actuation request input from the operator inputdevice. In the velocity control mode, the operating command includes aninstruction to move the one or more actuation devices at a rate ofchange corresponding to a rate of change of the actuation request inputfrom the operator input device.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features and advantages willbecome apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a work vehicle in the form of a motorgrader in which the operator control system of this disclosure may beincorporated;

FIG. 1B is a perspective view of a work vehicle in the form of a wheelloader in which the operator control system of this disclosure may beincorporated;

FIG. 2 is simplified view inside an operator cabin of the motor graderof FIG. 1A or the wheel loader of FIG. 1B showing example operator inputdevices;

FIG. 3 is a functional block diagram depicting dataflows of an operatorcontrol system on an example embodiment;

FIG. 4 is a perspective view of an active feedback force joystick devicethat may be implemented in the operator control system of FIG. 3according to an embodiment;

FIGS. 5A and 5B are schematic views of a passive feedback force joystickdevice that may be implemented in the operator control system of FIG. 3according to an embodiment;

FIGS. 6A-6C are cross-sectional views of a portion of the joystickdevice of FIG. 5A through line 6-6; and

FIGS. 7A-7C are cross-sectional views of a portion of the joystickdevice of FIG. 5A through line 7-7.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

The following describes one or more example embodiments of the disclosedoperator control system, as shown in the accompanying figures of thedrawings described briefly above. Various modifications to the exampleembodiments may be contemplated by one of skill in the art.

Generally, the disclosed operator control systems and methods (and workvehicles in which they are implemented) provide for improved operatorexperience to perform steering tasks as compared to conventional systemsby enabling the operator to select between a velocity-based controlstrategy and a position-based control strategy for steering or otheractuation devices, thereby simplifying steering and/or improvingoperation of the work vehicle for each operator.

Work vehicles used in various industries, such as the agriculture,construction and forestry industries, may include systems, tools, orimplements used to maneuver and carry out various functions for whichthe work vehicle was designed. Typically, this requires the vehicleoperator to be familiar with the vehicle devices for controlling thevehicle heading and speed and operating the implement. Certain workvehicles, such as those with a number of implements having multipledegrees of freedom in movement, may be rather complex to operate andrequire the operator to have considerable related skill and experience.Suboptimal operation of the vehicle or the implements may result ininefficient or imprecise performance at the work site or generallydiscourage potential operators from attempting to operate unfamiliar ordifferent vehicles.

One particularly complex work vehicle is the motor grader, which isgenerally used in the construction industry to set grade. Modern motorgraders are typically large machines with a lengthy articulated chassisformed by a front frame with steered wheels pivotally connected to arear frame with drive wheels. Motor graders may also have the capabilityto tilt the steered wheels. These features thus provide for an improved(i.e., shorter) turning radius, thereby making the large machine nimblerthan otherwise possible. Beyond the heading and speed control, motorgraders may have rather complex implements. The primary tool on motorgraders is the moldboard or blade, which is mounted to a turntable knownin the industry as a circle. The circle is adjustably mounted to thevehicle frame, and the blade in turn is adjustably mounted to thecircle, thus giving the blade a wide-range of possible movements. Othertypes of vehicles, such as wheel loaders, may present similaroperational complexities.

To perform the aforementioned functions and operations, the motorgraders and other types of vehicles may be outfitted with a relativelylarge number of joysticks, control levers, buttons, switches, knobs, andother devices that may each control operation of a single, discreteoperation or motion. As examples, one arrangement includes a dualjoystick control system with left and right multi-axis joystick devicesthat, in addition to multiple inputs by manipulation of the joystickgrip interfaces, each carry a large number of other input devices. Inone example, manipulation of one of the joystick devices along one axismay control the steering system (e.g., pivoting the steered wheels tothe right and left). Such steering must be performed along with numerousother possible control functions. Even though the steering control isalready challenging while undertaking the numerous other tasks, steeringcontrol issues may be compounded by the multiple control strategies thatmay vary from vehicle to vehicle. Certain operators may have a controlstrategy preference and/or unfamiliar operation may result ininefficiencies. Potential steering control strategies may include avelocity-based steering control strategy and a position-based steeringcontrol strategy. Additionally, although the steering system isdiscussed below, the control strategies may also be applicable to otheractuation devices on the work vehicle, including implement actuationdevices, such as booms, buckets, blades, and the like.

In a velocity-based steering (or other actuation) control strategy, anoperator control system generates velocity-based commands in response tovelocity-based operator inputs to control the associated actuationdevices of the work vehicle. Generally, in the velocity-based steeringcontrol strategy, the position (e.g., the absolute position or anglerelative to neutral) of the actuation request input at the operatorinput device is interpreted to request a command to move an actuationdevice at a corresponding rate of change. As such, a relatively smallamount of movement by the operator input device to a particular positionmay thus correspond to a relatively slower movement of the associatedactuation device as long as the position of the operator input device ismaintained, as compared to a larger movement by the operator inputdevice, which results in a relatively faster movement of the associatedactuation device. As such, the controller may thus receivevelocity-based input commands corresponding to a desired movement of themachine or implement, and the controller may resolve the velocity-basedinputs, possibly in conjunction with inputs from sensors or otherposition-indicating devices, and command one or more target actuationdevice velocities (e.g., depending on the number of actuation devicesrequired to effectuate the desired end movement). The joystick deviceadditionally provides a feedback force in accordance with thevelocity-based steering control strategy. In particular, in thevelocity-based steering control strategy, the operator makes theintended control input (e.g., joystick device movement) and then letsthe control input return to a neutral position without continuing tohold the joystick grip interface until the actuation device movementcycle time is completed, as may be required in a position-based steeringcontrol strategy. Typically, the velocity-based steering controlstrategy implements a feedback force opposing the direction of inputthat increases as the joystick grip interface moves away from theneutral position and decreases as the joystick grip interface movestowards the neutral position. As an example, a curve the depictsfeedback force in view of joystick grip interface angle according to thevelocity-based steering control strategy may have a V-shaped appearancethat is centered about the neutral position.

In a position-based steering (or other actuation) control strategy, anoperator control system generates position-based commands in response toposition-based operator inputs to control the associated actuationdevices of the work vehicle. Generally, in the example of a joystick,the position of an actuation request at the operator input devicerelative to a neutral position is interpreted by the controller torepresent the desired corresponding position (e.g., angle) of thesteering system in the designated direction. Moreover, rate at which thejoystick grip interface is moved may be considered by the controller torepresent the desired speed at which to implement the command. As such,the controller may thus receive position-based input commandscorresponding to a desired movement of the machine or implement, and thecontroller may resolve the position-based inputs, possibly inconjunction with inputs from sensors or other position-indicatingdevices, and command one or more target actuation device positions(e.g., depending on the number of actuation devices required toeffectuate the desired end movement). The operator input deviceadditionally provides a feedback force in accordance with theposition-based steering control strategy. In particular, in theposition-based scheme, the operator makes the intended control input(e.g., joystick movement) and then the joystick grip interface generallystays in that position until adjusted by the operator, thereby providinga stabilizing feedback force. In addition to this aspect of the feedbackforce, the position-based steering control strategy typically implementsa further feedback force opposing the direction of input that increasesas the joystick moves away from an initial position, which may or maynot be the neutral position. In this instance, the feedback forcerepresents an overspeed response corresponding to the reaction of thesteering system. In other words, as the joystick grip interface is movedquickly from a neutral position, the feedback force will be relativelyhigh to, in effect, enable implementation of the corresponding command,while if the joystick is moved slowly from a neutral position, thefeedback force will be relatively low since the steering system has timeto react appropriately. In position-based steering control strategies,this feedback force function is also applicable to initial positionsother than the neutral position. As an example, the feedback force-anglecurve of a position-based steering control strategy may have a V-shapedappearance that is centered about the current position that is laggedbased on steering system articulation.

Now with reference to the drawings, one or more example implementationsof the operator control system for use on a work vehicle will now bedescribed. While a motor grader is illustrated and described herein asan example work vehicle, one skilled in the art will recognize thatprinciples of the operator control system disclosed herein may bereadily adapted for use in other types of work vehicles, including, forexample, various crawler dozer, loader, backhoe and skid steer machinesused in the construction industry, as well as various other machinesused in the agriculture and forestry industries. As such, the presentdisclosure should not be limited to applications associated with motorgraders or the particular example motor grader shown and described.Similarly, the operator control systems are discussed below with respectto the steering system. However, other systems may implementcorresponding operator control systems in which velocity-based andposition-based control strategies may be applicable.

As shown in FIG. 1, a motor grader 100 includes an operator controlsystem 110 that controls various functions associated with the motorgrader 100, including a steering function based on manual inputs from anoperator and other inputs, as discussed in greater detail below. Theoperator control system 110 is implemented with a controller 120 and mayfurther be considered to include one or more operator input devices 130and/or a steering system 140. Generally, as described in greater detailbelow, the operator input devices 130 may include one or more operatorcontrol apparatuses 132, 134 (e.g., as joystick-type or other types ofcontrols) to receive operator inputs that control various aspects of themotor grader 100 and a steering mode selection switch 136 to receiveoperator inputs that select a mode associated with a control strategy.Additional details about the operator control system 110 will beprovided below after a more general description of the motor grader 100.

In the depicted example, the motor grader 100 is formed by a front frame150 and a rear frame 152 that are pivotably connected to each other viaan articulation joint 154. The front frame 150 and the rear frame 152are respectively supported by front wheels 156 and rear wheels 158. Inother embodiments, the motor grader 100 may include otherground-engaging devices for propelling the machine, such as trackassemblies, for example, as known in the art.

The motor grader 100 further includes a drive system 160 adapted todrive or power the motor grader 100 and collectively formed by an engineor other type of power source 162, and a transmission 164 supported, inthis example, by the rear frame 152. The engine 162 may be any suitabletype of engine, including a diesel engine, a gasoline engine, a gaseousfuel powered engine such as a natural gas engine, or any other type ofengine apparent to one skilled in the art. Other power sources mayalternatively embody a non-combustion source of power such as a fuelcell, a power storage device, an electric motor, or other similarmechanism. Although not shown in detail, the transmission 164 includes aplurality of forward and reverse gears and a neutral gear and isconnected to a differential axle for driving one or more of the rearwheels 158 based on torque from the engine 162. In some embodiments, themotor grader 100 may include an all-wheel drive system in which one ormore of the front wheels 156 are also driven.

An operator cab 170 is mounted to the front frame 150. The operator cab170 may contain many controls of the motor grader 100, includingoperator input devices 130 described in greater detail below, used tosteer and otherwise operate the motor grader 100. The operator cab 170may also include a display device 172 adapted to convey information tothe operator concerning the operation of the motor grader 100. In someexamples, the display device 172 may accept operator inputs (e.g., as atouchscreen display) such that the display device 172 may also beconsidered to be one of the operator input devices 130.

As introduced above, the motor grader 100 includes the steering system140 to maneuver the motor grader 100 during operation based on signalsfrom the controller 120 and/or operator input devices 130 according to aselected steering control strategy, described in greater detail below.As is generally known, the steering system 140 includes variouslinkages, levers, joins, gears, pins, rods, and the like to position oneor more driven wheels 156, 158 to orient the motor grader 100 in thedesired direction. In one example and as schematically shown in FIG. 1,the steering system 140 includes one or more steering actuation devices,such as one or more steering cylinders 142 (schematically shown) coupledto the front or rear wheels 156, 158 configured to be hydraulicallyoperated to articulate or reposition of the wheels 156, 158 (e.g.,pivoting about a vertical axis) to steer the motor grader 100.Additional steering mechanisms may be provided, including one or morelean cylinders 144 (schematically shown) coupled to the front or rearwheels 156, 158 configured to be hydraulically operated to control theposition of the wheels 156, 158 (e.g., pivoting about a horizontalaxis). Further, the steering system 140 may include one or morearticulation cylinders 146 (schematically shown) mounted to one or bothof the frames 150, 152 to rotate the front frame 150 relative to therear frame 152 about the articulation joint 154. The components of thesteering system 140 introduced above are merely examples, and any numberof additional components or systems may be provided. For example, thesteering system 140 may further incorporate various types of circuits,including a hydraulic circuit and/or an electrical circuit forfacilitating and controlling operation of the cylinders 142, 144, 146and other actuation devices of the steering system 140. Although notshown, such a hydraulic circuit may include hoses, pumps, tanks, valves,and the like.

The motor grader 100 includes one or more implements 180, 182 forperforming work functions. As examples, the motor grader 100 includes acircle 180 and blade assembly 182 are mounted to the front frame 150 infront of the operator cab 170. Various types of actuators (as well asbrackets, couplings, motors, hydraulic and electric components, etc.)are provided to manipulate the circle 180 and/or blade assembly 182,including lifting, tilting, rotating, shifting, repositioning, and thelike to advantageously perform the functions of the motor grader 100.Other implements may be provided.

As noted above, the controller 120 is provided to control variousoperational aspects of the motor grader 100. Generally, the controller120 may receive inputs from a number of sources, including the operatorvia the operator input devices 130 and from various sensors, units, andsystems onboard or remote from the motor grader; and in response, thecontroller 120 generates one or more types of commands forimplementation by the various systems of motor grader 100. As oneexample discussed in greater detail below, the controller 120 mayfacilitate operation of the operator control system 110, particularlywith respect to receiving steering or other actuation request inputsfrom the operator via the operator input devices 130 and generatingassociated steering or other actuation device commands for the steeringsystem 140 based on a selected mode associated with a respective controlstrategy.

Broadly, the controller 120 may be configured as a computing device withassociated processor devices and memory architectures, as a hard-wiredcomputing circuit (or circuits), as a programmable circuit, as ahydraulic, electrical or electro-hydraulic controller, or otherwise. Assuch, the controller 120 may be configured to execute variouscomputational and control functionality with respect to the motor grader100 (or other machinery). In some embodiments, the controller 120 may beconfigured to receive input signals in various formats (e.g., ashydraulic signals, voltage signals, current signals, and so on), and tooutput command signals in various formats (e.g., as hydraulic signals,voltage signals, current signals, mechanical movements, and so on). Insome embodiments, the controller 120 (or a portion thereof) may beconfigured as an assembly of hydraulic components (e.g., valves, flowlines, pistons and cylinders, and so on), such that control of variousdevices (e.g., pumps or motors) may be implemented with, and based upon,hydraulic, mechanical, or other signals and movements.

The controller 120 may be in electronic, hydraulic, mechanical, or othercommunication with various other systems or devices of the motor grader100 (or other machinery). For example, the controller 120 may be inelectronic or hydraulic communication with various actuators, sensors,and other devices within (or outside of) the motor grader 100, includingvarious devices associated with pumps, control valves, and so on. Thecontroller 120 may communicate with other systems or devices (includingother controllers) in various known ways, including via a CAN bus (notshown) of the motor grader 100, via wireless or hydraulic communicationmeans, or otherwise. An example location for the controller 120 isdepicted in FIG. 1. It will be understood, however, that other locationsare possible including other locations on the controller 120, or variousremote locations.

In some embodiments, the controller 120 may be configured to receiveinput commands and to interact with an operator via the operator inputdevices 130, which may be disposed inside an operator cab 170 of themotor grader 100 for easy access by the operator. The operator inputdevices 130 may be configured in a variety of ways. In some embodiments,the operator input devices 130 may include one or more joystick devices,various switches or levers, one or more buttons, a touchscreen interfacethat may be overlaid on a display, a keyboard, an audible device, amicrophone associated with a speech recognition system, or various otherhuman-machine interface devices. In one example, the one or moreswitches (e.g., switch 136) may receive an input associated with asteering mode selection and a joystick (or other) device (e.g.,apparatuses 132, 136) may receive steering requests associated with thesteering system 140 according to a selected steering mode to implementan associated steering control strategy. More specific examples ofoperator input devices 130 are provided below with reference to FIG. 2.

Various sensors (not shown) may also be provided to observe variousconditions and other parameters associated with the motor grader 100.For example, various sensors may be associated with the steering system140, drive system 160, and/or the implements 180, 182. Example sensorsinclude sensors for measuring the articulation angle at the articulationjoint 154; pressure and/or position sensors to evaluate the positions ofthe various cylinders, pumps, and valves; travel speed sensors; steeringfeedback angle sensors; and steering velocity sensors. One or moresensors may also be incorporated into the operator input devices 130,discussed below.

As shown in FIG. 1B, a wheel loader 100′ includes an operator controlsystem 110′ that controls various functions associated with the wheelloader 100′ in a similar manner to the motor grader 100 discussed inreference to FIG. 1A, including steering or other actuation functionsbased on manual inputs from an operator and other inputs, as discussedin greater detail below. As above, the operator control system 110′ isimplemented with a controller 120′ and may further be considered toinclude one or more operator input devices 130′ and/or a steering system140′. Generally, the operator input devices 130′ may include one or moreoperator control apparatuses 132′, 134′ (e.g., as joystick-type or othertypes of controls) to receive operator inputs that control variousaspects of the wheel loader 100′ and a mode selection switch 136′ toreceive operator ii inputs that select a mode associated with a controlstrategy (e.g., a steering or other actuation control mode). Additionaldetails about the operator control system 110′ will be provided belowafter a more general description of the loader 100′.

In the depicted example, the wheel loader 100′is formed by a chassis orframe 150′ supported by front wheels 156′ and rear wheels 158′. In otherembodiments, the wheel loader 100′ may include other ground-engagingdevices for propelling the machine, such as track assemblies, forexample, as known in the art. The wheel loader 100′ further includes adrive system 160′ adapted to drive or power the wheel loader 100′ andcollectively formed by an engine or other type of power source 162′ anda transmission 164′, as generally described above.

An operator cab 170′ is mounted to the frame 150′. The operator cab 170′may contain many controls of the wheel loader 100′, including operatorinput devices 130′ described in greater detail below, used to steer andotherwise operate the wheel loader 100′. The operator cab 170′ may alsoinclude a display device 172′ adapted to convey information to theoperator concerning the operation of the wheel loader 100′. In someexamples, the display device 172′ may accept operator inputs (e.g., as atouchscreen display) such that the display device 172′ may also beconsidered to be one of the operator input devices 130′.

As introduced above, the wheel loader 100′ includes the steering system140′ to maneuver the wheel loader 100′ during operation based on signalsfrom the controller 120′ and/or operator input devices 130′ according toa selected steering control strategy, described in greater detail belowas one example. As is generally known, the steering system 140′ includesvarious linkages, levers, joins, gears, pins, rods, and the like toposition one or more driven wheels 156′, 158′ to orient the wheel loader100′ in the desired direction. In one example and as schematically shownin FIG. 1B, the steering system 140′ includes one or more steeringactuation devices, such as one or more steering cylinders 142′(schematically shown) coupled to the front or rear wheels 156′, 158′configured to be hydraulically operated to articulate or reposition ofthe wheels 156′, 158′ (e.g., pivoting about a vertical axis) to steerthe wheel loader 100′. Additional steering mechanisms may be provided.The components of the steering system 140′ introduced above are merelyexamples, and any number of additional components or systems may beprovided. For example, the steering system 140′ may further incorporatevarious types of circuits, including a hydraulic circuit and/or anelectrical circuit for facilitating and controlling operation of thecylinders 142′ and other actuation devices of the steering system 140′.Although not shown, such a hydraulic circuit may include hoses, pumps,tanks, valves, and the like.

The wheel loader 100′ further includes a work implement, such as abucket 180′, positioned at a front of the wheel loader 100′ and attachedto the wheel loader 100′ through one or more linkage arms 182′ thatinclude a series of pinned joints, structural members, and at least onehydraulic actuator 184′. This configuration allows the bucket 180′ to bemoved up and down relative to the ground, and rotate around a lateralaxis of the work vehicle 100′. Other implements may be provided.

Generally, the controller 120′ of the wheel loader 100′ operates in amanner similar to that described above with respect to the controller120 of the motor grader 100 to control various operational aspects ofthe motor grader 100. In particular, the controller 120′ may receiveinputs from a number of sources, including the operator via the operatorinput devices 130′ and from various sensors, units, and systems onboardor remote from the wheel loader 100′; and in response, the controller120′ generates one or more types of commands for implementation by thevarious systems of wheel loader 100′. As one example discussed ingreater detail below, the controller 120′ may facilitate operation ofthe operator control system 110′, particularly with respect to receivingsteering request inputs from the operator via the operator input devices130′ and generating associated steering actuation device commands forthe steering system 140′ based on a selected mode associated with arespective control strategy.

Reference is briefly made to FIG. 2, which depicts the interior cabin ofthe operator cab 170 of the motor grader 100, although the cab 170 anddescription below may also refer to the wheel loader 100′. As shown, theoperator cab 170 provides an enclosure for the operator to access anumber of different operator input devices 130, including a steeringwheel, accelerator, and brake pedals. The operator cab 170 may furtherhouse the display device 172. In this example, the operator inputdevices 130 include operator control apparatuses 132, 134 as a leftoperator control apparatus 132 and a right operator control apparatus134 mounted to each side of the operator seat.

The operator control apparatuses 132, 134 are joystick-type controlswith a grip interface and various types of inputs, such as buttons,switches, and dials, mounted on the grip interface. In one example, theleft operator control apparatus 132 may include input mechanisms forlifting, lowering, and adjusting the pitch of the blade assembly 182;rotating the circle 180; shifting the transmission 164; and certainauxiliary functions. As a further example, the right operator controlapparatus 134 may include input mechanisms for shifting the circle 180and the blade assembly 182; adjusting the lean of the wheels 156, 158;adjusting the articulation of the frames 150, 152; and locking thedifferential axle.

According to one embodiment of the operator control system 110 withrespect to the steering system 140, the left operator control apparatus132 includes a joystick grip interface that may be pivoted to the leftand right as a steering request to steer the front wheels 156 via thesteering system 140. In particular, the operator provides manualoperator steering inputs by pivoting the joystick grip interface, andthe controller 120, upon receiving the steering inputs, generatesappropriate steering actuation device commands to the steering system140. Although the steering function is discussed below with respect tothe joystick device, the steering function may be implemented into otheroperator input devices 130, such as the right operator control apparatus134, steering wheel, and/or the other buttons, dials, and the like.Additional details about example implementations of a joystick devicewill be provided below.

As also depicted in FIG. 2, the operator input devices 130 furtherinclude the steering mode selection switch 136 that may form part of theoperator control system 110. The steering mode selection switch 136 maytake any form. In one example, the steering mode selection switch 136 isa mechanical, physical, and/or virtual switch that enables an operatorto select between a velocity-based steering control strategy (e.g., as avelocity control mode) and a position-based steering control strategy(e.g., as steering control mode), as will be discussed in greater detailbelow. In one example, the steering mode selection switch 136 may havevisual indicia reflecting the potential strategies of the system 110such that the operator may position the switch 136 according to thedesired strategy. As introduced above, switch 136 of the motor grader100 may be analogous to the switch 136′ of the wheel loader 100′.

Reference is now made to FIG. 3, which is a functional block dataflowdiagram of portions of the operator control system 110 (and operatorcontrol system 110′) according to an embodiment. As noted above, theoperator control system 110, 110′ may be considered to include thecontroller 120, 120′, the steering system 140, 140′ with one or moreactuation devices 142, 142′, and one or more operator input devices 130,130′. Generally, the actuation devices 142, 142′ discussed below mayrefer to any individual or combination of actuation devices andassociated components that may be utilized to steer the motor grader 100or wheel loader 100′, In this example, the operator input devices 130,130′ include a joystick device 350 and the steering mode selectionswitch 136, 136′ (such as the steering mode selection switches 136, 136′of FIG. 1A or 1B). The display device 172, 172′ (such as the displaydevice 172, 172′ of FIG. 1A or 1B) may also form part of the operatorcontrol system 110, 110′.

In one example, the joystick device 350 may be incorporated into alarger operator control apparatus, such as one of the operator controlapparatuses 132, 132′, 134, 134′, with numerous operator inputmechanisms. However, for the purpose of steering the front wheels of thesteering system 140, 140′ as part of the operator control system 110,110′, the joystick device 350 is a single-axis joystick unit that may bepivoted to the left and right by the operator in order to steer themotor grader 100 (FIG. 1A) or the wheel loader 100′ (FIG. 1B).Generally, the joystick device 350 described below in reference to FIG.3 may be implemented in any suitable manner; however, more specificexample implementations are described below with reference to FIGS. 4,5A, 5B, 6A-6C, and 7A-7C.

As shown, the joystick device 350 includes a joystick grip interface 352mounted to a base or housing 354. The joystick grip interface 352 is alever-type or shaft element with a first end engageable by an operatorand a second end secured to pivot within the housing 354 about a pivotaxis. The operator engages the joystick grip interface 352 along a rangeof motion to implement a desired steering or other actuation function ofthe motor grader 100 or the wheel loader 100′ as an operator steeringinput 370, as described below.

A feedback unit 356 is coupled to the joystick grip interface 352 or thebase 354 in order to impart a feedback force in response to the operatormanipulation of the joystick grip interface 352. As used herein, theterm “feedback” refers to a force imparted on the joystick gripinterface 352 in any form or for any purpose, including a force tocounteract or resist operator manipulation or external forces, a forceto maintain a position of the grip interface 352 in the absence ofoperator manipulation, or a force to center or reposition the gripinterface 352 (e.g., to a neutral position or otherwise) in the absenceof operator manipulation. In general, the feedback unit 356 applies thehaptic feedback force or “feel” responsive to operator movements. Thefeedback force may be linear or non-linear and proportional to the forcerequired to move the grip interface 352. As described below, thefeedback unit 356 is commanded to apply the force in view of thesteering control strategy.

The joystick device 350 further includes at least one control interfacesensor 358 configured to collect various types of information associatedwith the operator steering input 370. In particular, with respect to thejoystick grip interface 352, the control interface sensor 358 isconfigured to collect data associated with the position or displacementangle relative to a neutral position and the speed or angular velocityof the displacement (or derivations thereof), and in response, thecontrol interface sensor 358 generates a corresponding signal in theform of an actuation request input 382. The actuation request input 382is provided to the controller 120, 120′.

As introduced above, the operator input devices 130, 130′ furtherinclude the steering mode selection switch 136, 136′. The steering modeselection switch 136, 136′ is configured to receive an operator modeinput 372 in which the operator selects between a velocity control modeimplementing the velocity-based steering control strategy and a positioncontrol mode implementing the position-based steering control strategy.In response to the operator mode input 372, the steering mode selectionswitch 136, 136′ generates a corresponding signal in the form of acontrol mode selection input 380. The control mode selection input 380is provided to the controller 120, 120′.

As such, the controller 120, 120′ may receive the control mode selectioninput 380 and actuation request input 382. With respect to the operatorcontrol system 110, 110′ of FIG. 3, the controller 120, 120′ may beorganized as one or more functional units or modules 310, 320, and 330(e.g., software, hardware, or combinations thereof). As can beappreciated, the modules 310, 320, 330 shown in FIG. 3 may be combinedand/or further partitioned to carry out similar functions to thosedescribed herein. As an example, each of the modules 310, 320, 330 maybe implemented with processing architecture such as a processor 302 andmemory 304, as well as suitable communication interfaces. For example,the controller 120, 120′ may implement the modules 310, 320, 330 withthe processor 302 based on programs or instructions stored in memory304. In this example, the controller 120, 120′ includes a mode module310, an actuation module 320, and a feedback module 330. In someembodiments, the feedback module 330 may be omitted, as described below.

As introduced above, the controller 120, 120′ is configured to receivethe actuation request input 382 and the control mode selection input380. In one embodiment, the mode module 310 receives the control modeselection input 380. The mode module 310 evaluates the control modeselection input 380, and in response, generates a control modedetermination 312 that identifies the selected control mode representedin the control mode selection input 380. The control mode determination312 is provided to the actuation module 320 and feedback module 330.

The actuation module 320 receives the actuation request input 382 andthe control mode determination 312. The actuation module 320 evaluatesthe actuation request input 382 in view of the control modedetermination 312. The actuation module 320 may access storedinformation that maps the actuation request input 382 to a work deviceoperating command 390 according to the current control modedetermination 312. Specifically, an actuation request input 382, when inthe velocity control mode, is mapped to one or more work deviceoperating commands 390 in order to implement a particular velocity; andan actuation request input 382, when in the position control mode, ismapped to a work device operating command 390 in order to implement aparticular position. For example, in the velocity control mode, theactuation request input 382 is interpreted as a joystick grip interfaceinput, and in response, the actuation module 320 may reference a storedmap to determine a corresponding velocity command for one or more of thesteering actuation devices 142, 142′ that results in an operator desiredsteering velocity. Such reference maps may include a collection of datain the form of tables, graphs, and/or equations. Similarly, in theposition control mode, the actuation request input 382 based on theoperator steering input 370 is interpreted as a joystick grip interface(or other operator interface) position input, and in response, theactuation module 320 may reference a stored map to determine acorresponding position command for one or more of the steering actuationdevices 142, 142′ that results in an operator desired steering position.

The work device operating command 390 generated by the actuation module320 is provided to the steering system 140, 140′, such as one or more ofthe steering actuation devices 142, 142′, as introduced above. Forexample, the work device operating command 390 may correspond to valvepositions to operate the actuation devices 142, 142′ to a specifiedposition or velocity. Accordingly, the steering system 140, 140′implements the work device operating command 390 for the control modedetermination 312, thereby enabling steering operation with steeringinputs 370 according to a desired or preferred steering controlstrategy.

In some embodiments, the actuation module 320 may receive additionalinput data (not shown) from various sensors, systems, or other moduleson-board or off-board of the motor grader 100 or wheel loader 100′. Suchadditional input may include information associated with the actuationdevices 142, 142′ (e.g., cylinder positions, tank volumes, fluidpressures, etc.). The actuation module 320 may further evaluate theactuation request input 382 in view of the additional input to providean appropriate operating command 390.

In some examples, the mode module 310 may further provide the controlmode determination 312 to the display device 172, 172′. This enables avisual indication to the operator of the present steering control mode.

The mode module 310 further provides the control mode determination 312to the feedback module 330. The feedback module 330 also receives theactuation request input 382. In turn, the feedback module 330 mayactively generate an appropriate feedback command 392 in response to theactuation request input 382 according to the control mode determination312 for the feedback unit 356 of the joystick device 350. In oneexample, the feedback module 330 may access stored information that mapsthe actuation request input 382 in view of the control modedetermination 312 to an associated feedback force response as a feedbackcommand 392. Specifically, an actuation request input 382, when in thevelocity control mode, is mapped to one or more feedback commands 392 inorder to implement a particular feedback force according to avelocity-based steering control strategy; and an actuation request input382, when in the position control mode, is mapped to one or morefeedback commands 392 in order to implement a particular feedback forceaccording to a position-based steering control strategy. Such referencemaps may include a collection of data in the form of tables, graphs,and/or equations.

Upon receipt, the feedback unit 356 applies a force to the joystick gripinterface 352 according to the feedback command 392. As a result, thesteering control mode dictates the nature of the feedback forcegenerated by the feedback unit 356 on the joystick grip interface 352.

In some examples, the feedback module 330 may be omitted. In thoseembodiments, the feedback force may be applied passively to the joystickdevice 350, e.g., without active control. Additional details regardingthe feedback unit 356, including example mechanisms for applying thefeedback force, are provided below.

In this manner, the operator control system 110, 110′ enables theoperator to select a steering mode and provide steering inputs, and inresponse, the controller 120, 120′ implements these inputs toappropriately control the steering system 140, 140′. The controller 120,120′ may additionally generate the appropriate feedback force at thejoystick device 350 according to the selected mode.

In various embodiments of the operator control system 110, 110′described above, the velocity-based and position-based steering controlstrategies may be implemented according to various types of operatorinput devices and associated feedback responses. For example, theoperator input devices may be implemented in an active system in which amotor generates an appropriate feedback response; a passive system inwhich mechanical components generate the feedback response; and asemi-active system that includes implementation characteristics of apassive system and an active system. Examples are provided below withreference to FIGS. 4, 5A, 5B, 6A-6C, and 7A-7C. Additionally, as notedabove, although the operator control system 110, 110′ is primarilydescribed in the context of steering, corresponding strategies may beutilized with other actuation operations.

Reference is made to FIG. 4, which is an active (or full-active)feedback force joystick device 400. In one embodiment, the joystickdevice 400 is an electromechanical joystick device. The joystick device400 of FIG. 4 may be considered one of the operator input devices 130 ofthe operator control system 110, 110′ discussed above with reference toFIGS. 1A, 1B, 2, and 3.

The joystick device 400 includes a joystick grip interface (or joystickshaft) 410 that extends between a first end 412 configured forengagement by the operator to a second end within a housing or basemember. Although not shown, the second end of the joystick gripinterface 410 is pivotally coupled to a positioning motor 430 via anysuitable linkage arrangement, such as gimbal arm, pivot bearing, bearingmount, gear arrangements, and the like.

A positioning motor 430, such as a servo motor, is operatively coupledto the joystick grip interface 410 via various mechanisms such that adesired force and/or velocity can be applied to the control joystickgrip interface 410 having a magnitude that is a function of the torqueand/or velocity of a motor drive shaft (not shown).

One or more electromechanical or optical position sensors 440(schematically shown) are operatively coupled to the joystick gripinterface 410 to determine the position of the joystick grip interface410. Examples of such sensors 440 include rotary or linearpotentiometers, optical encoders, and linear displacement voltagetransducers (LDVTs).

In FIG. 4, the joystick grip interface 410 is in a neutral or centerposition. During operation, a force applied by the operator pivots thejoystick grip interface 410 relative to the steering axis, and thuspivots a linkage arrangement to cause rotation of the drive shaft of themotor 430. The amount of rotation imparted to drive shaft may be sensedby sensors 440 that output a corresponding signal representing anactuation request signals (e.g., actuation request input 382 of FIG. 3).

Additionally, the motor 430 is configured to generate a feedback forceapplied to the joystick grip interface 410 in response according tocommand signals (e.g., feedback command 392 of FIG. 3). In particular,the motor 430 applies a feedback force in order to move or resistmovement of the joystick grip interface 410. The motor 430 may implementthe variable feedback force according to the selected control mode,e.g., either the velocity-based steering control strategy in thevelocity control mode or the position-based steering control strategy inthe position control mode.

As examples, in the velocity control mode, the feedback force curveremains centered, regardless of the position of the joystick gripinterface 410. As such, as the joystick grip interface 410 is movedfurther from the center, the motor 430 applies an increasing feedbackforce to the joystick grip interface 410 in an opposing direction,although typically less than the force required to move the joystickgrip interface 410. Moreover, the feedback force from the motor 430functions to re-center the joystick grip interface 410 after theoperator releases the joystick grip interface 410. Based on the feedbackcommands, the feedback force may be linearly or non-linearlyproportional to the force required to move the joystick grip interface410.

In the position control mode, the feedback force curve follows theposition of the joystick grip interface 410. As such, as the joystickgrip interface 410 completes a movement, the feedback force applied bythe motor 430 operates to maintain the position of the joystick gripinterface 410 associated with the operator input. As introduced above,the motor 430 may additionally provide a feedback force in view of thespeed of the operator input according to the reaction time of thesteering system (e.g., steering system 140 of FIG. 1A, as well assteering system 140′ of FIG. 1B). In particular, if the joystick gripinterface 410 is moved quickly, the motor 430 may apply a relativelystrong resisting feedback force to the joystick grip interface 410. Theresisting feedback force reflects the ability of the steering system toimplement the actuation request input. Otherwise, the steering systemmay not be able to “keep up” with the inputs at the joystick gripinterface 410.

In some examples, the feedback force applied by the motor 430 may havecharacteristics of both the velocity-based steering command strategy andthe position-based steering command strategy regardless of the currentsteering control mode in order to improve the function of the joystickdevice 400. For example, in the velocity control mode, the motor 430operates to provide some stabilizing feedback force to the joystick gripinterface 410 upon returning to the neutral position. Otherwise, thejoystick grip interface 410 may undesirably oscillate upon returning tothe neutral position. Similarly, in the position control mode, the motor430 operates to provide some stabilizing feedback force on the joystickgrip interface 410, even when the joystick grip interface 410 has beenreleased by the operator. Otherwise, the weight of the joystick gripinterface 410 may cause unwanted movement. Instead, the feedback forceof the motor 430 may automatically account for the weight of thejoystick grip interface 410 such that when the interface 410 isreleased, it stays in the position. However, the selected modedesignates which strategy dominates the applicable feedback force.

Reference is now made to FIGS. 5A-5B, 6A-6C, and 7A-7C, which aredifferent views of a passive (or full-passive) feedback force joystickdevice 500. The joystick device 500 may be considered one of theoperator input devices 130, 130′ of the operator control system 110,110′ discussed above with reference to FIGS. 1A, 1B, 2, and 3. In thisexample, the joystick device 500 is incorporated with a steering modeselection switch 510, which may correspond to the steering modeselection switch 136 also discussed above with reference to FIGS. 1A,1B, 2, and 3.

Initially referring to FIG. 5A, the joystick device 500 includes ajoystick grip interface 530 that extends between a first end 532configured for engagement by the operator to a second end 534 within ahousing or base member 536. The second end 534 of the joystick gripinterface 530 is pivotally coupled to a pivot collar 540 to pivot abouta pivot axis 542.

The joystick device 500 further includes a feedback unit 550 thatfunctions to provide velocity-based feedback force and position-basedfeedback force on the joystick grip interface 530 based on operatorselections from the steering mode selection switch 510. In particular,the feedback unit 550 includes a velocity-based feedback pack 560 and aposition-based feedback pack 570, as described in greater detail below.The feedback packs 560, 570 discussed below are merely examples on thenumerous types of feedback mechanisms that may be implemented accordingto the embodiments discussed herein.

The joystick device 500 additionally includes one or more sensors 580.As the joystick grip interface 530 pivots about the pivot axis 542, thesensor 580 collects information associated with one or more of theposition and velocity of the joystick grip interface 530, including theposition and the velocity resulting from the operator input on thejoystick grip interface 530, which results in the actuation requestinput (e.g., input 382 of FIG. 3). As described in greater detail below,the sensor 580 additionally collects information associated with theoperator mode selection on the steering mode selection switch 510. Thesensor 580 provides the actuation request input and the operatorstrategy selection input to an operator system controller (e.g., thecontroller 120, 120′), as described above. In one example, the sensor580 includes one or more of a rotary hall effect sensor, a reed switch,or a hall effect sensor.

The steering mode selection switch 510 includes an operator engagementinterface, such as a knob 512, coupled to a rod 514 terminating at a cam516. The cam 516 has a gear engagement that is coupled to an engagementrod 520. As a result of this arrangement, twisting of the knob 512operates to shift the engagement rod 520 along the pivot axis 542 backand forth (i.e., to the left and right in FIG. 5A). In effect, theengagement rod 520 is a link between the switch 510 and thevelocity-based feedback pack 560 and the position-based feedback pack570. As noted above, the knob 512 may be surrounded by indiciareflecting knob positions corresponding the respective modes

The engagement rod 520 has a first end 522 coupled to a cam 516, acenter portion 524 that extends through the housing 536 of the joystickdevice 500, and an end portion 526 positioned in one of thevelocity-based feedback pack 560 or the position-based feedback pack570, depending on the position of the steering mode selection switch510. As described below, the engagement rod 520 may have at least twopositions corresponding to the position of the steering mode selectionswitch 510, including: a first position (as shown in FIG. 5A) in whichthe end portion 526 is positioned in the velocity-based feedback pack560; and a second position (as shown in FIG. 5B) in which the endportion 526 is positioned in the position-based feedback pack 570.

The engagement rod 520 has a first set of splines (or teeth) 525arranged on the center portion 524 that extend through the pivot collar540. The pivot collar 540 has internal splines or teeth 544 that engagethe splines 525 of the engagement rod 520. Regardless of the position ofthe engagement rod 520, the splines 525 of the engagement rod 520 meshwith the splines 544 of the pivot collar 540. As a result, when theinterface 530 pivots about the pivot axis 542, the engagement rod 520pivots with the interface 530. The splined arrangement enables theengagement rod 520 to slide relative to the pivot collar 540 whilemaintaining the pivoting engagement.

The engagement rod 520 has a set of teeth (or splines) 527 (as shown inFIGS. 6A-6C, 7A-7C) on the end portion 526. The other portions of theengagement rod 520, including the center portion 524 immediatelyproximate to the end portion 526, may be cylindrical or othercross-sectional shapes that have smaller cross-sectional areas than theteeth 527 on the end portion 526. As described below, the teeth 527 ofthe end portion 526 of the engagement rod 520 selectively engage thevelocity-based feedback pack 560 or the position-based feedback pack 570such that the selected pack 560, 570 may impose a force on the joystickgrip interface 530 via the engagement rod 520 and the pivot collar 540.

Reference is now made to FIGS. 6A-6C, which are cross-sectional views ofthe joystick device 500 through line 6-6 of FIG. 5A, particularlythrough the velocity-based feedback pack 560. In FIG. 6A, the joystickgrip interface 530 is in a neutral position; in FIG. 6B, the joystickgrip interface 530 has been moved leftward; and in FIG. 6C, the joystickgrip interface 530 has been moved rightward.

As shown, the velocity-based feedback pack 560 is a centering springpack and includes a centering spring 610 on a pivot bracket 630pivotally mounted on a planar rear wall 632 within a housing 602 and astationary bracket 670 fixedly mounted to the housing 602. In thisexample, the pivot bracket 630 includes a first (or cylindrical) wallelement 640 and second (or U-shaped) wall element 650.

The cylindrical wall element 640 of the pivot bracket 630 is pivotallycoupled to the rear wall 632 and generally cylindrical to define apassageway 642 therethrough that aligns with a corresponding passagewaythrough the rear wall 632. The cylindrical wall element 640 includes aplurality of internal teeth (or splines) 644 that circumscribe thepassageway 642. As shown, when the mode selection switch 510 is in theposition corresponding to the velocity control mode, the teeth 527 onthe engagement rod 520 engage the teeth 644 of the cylindrical wallelement 640 for rotational engagement, as discussed in greater detailbelow.

The U-shaped wall element 650 of pivot bracket 630 is pivotally coupledto the rear wall 632 and is formed with a curved section 652, a firstwall leg 654, and a second wall leg 656. The curved section 652surrounds, but is spaced apart from, a portion of the cylindrical wallelement 640. The first wall leg 654 extends linearly from one end of thecurved section 652 and the second wall leg 656 extends linearly from theother end of the curved section 652. The first and second wall legs 654,656 are parallel to each other. The U-shaped wall element 650 is fixedto the cylindrical wall element 640 to pivot therewith.

In this embodiment, the stationary bracket 670 extends between sidewalls 604, 606 of the housing 602. The stationary bracket 670 isgenerally parallel to the rear wall 632 and spaced axially apart fromthe wall elements 640, 650, 660 of the pivot bracket 630. The stationarybracket 670 include pins or stops 672, 674 that extend axially towardthe rear wall 632 on either side of the centering spring 610.

The centering spring 610 is formed by a center coil 612, a first springleg 614 extending linearly from a first end of the center coil 612, andsecond spring leg 616 extending linearly from a second end of the centercoil 612. As shown, the center coil 612 is wrapped around thecylindrical wall element 640, in between the cylindrical wall element640 and the U-shaped wall element 650. The spring 610 is fixedly engagedto the cylindrical wall element 640. In the neutral position, the firstand second spring legs 614, 616 extend parallel to one another, alongthe first and second wall legs 654, 656, respectively.

Accordingly, when the operator desires to implement a steering functionin a velocity control mode, the operator rotates the knob 512 to aposition representing the velocity control mode. When the knob 512 isrotated into the position corresponding to the velocity control mode,the engagement rod 520 is translated by the rod 514 and cam 516. Uponmovement or repositioning of the engagement rod 520, the sensor 580determines the position of the engagement rod 520 and sends a controlmode selection input (e.g., input 380) to the controller 120, 120′, asdiscussed above. Upon the linear translation of the engagement rod 520into the position reflected by the knob 512 for the velocity controlmode, the teeth 527 at the end portion 526 of the engagement rod 520mesh with the teeth 644 in the cylindrical wall element 640 of the pivotbracket 630 of the velocity-based feedback pack 560. In this position,the center portion 524 (FIG. 5) of the engagement rod 520 extendsthrough a passageway (discussed below) in the position-based feedbackpack 570 such that the engagement rod 520 is not engaged with theposition-based feedback pack 570.

Because the engagement rod 520 is engaged with the velocity-basedfeedback pack 560, the joystick device 500 behaves in anoperator-accustomed manner for a velocity-based steering controlstrategy, as discussed below. As shown in FIG. 6A, in a neutralposition, the joystick grip interface 530 is positioned in a verticalorientation, although the neutral position may correspond to otherangles relative to the ground plane in other embodiments based on theshape of the interface 530, ergonomics, or other considerations. Asnoted above, when the joystick grip interface 530 and thus thevelocity-based feedback pack 560 are in the neutral position, the firstand second spring legs 614, 616 of the spring 610 are parallel to oneanother and respectively engage the stops 672, 674 of the stationarybracket 670, which maintain the spring 610 and thus, the pivot bracket630, engagement rod 520, pivot collar 540, and joystick grip interface530 in the generally neutral position according to a centeringequilibrium of the spring force.

During an operator steering input in a leftward direction, the forceapplied by the operator moves the joystick grip interface 530 to anangle offset from the vertical, as shown in FIG. 6B. During thispivoting movement, the splined connection between the pivot collar 540and the engagement rod 520 causes the engagement rod 520 to rotate. Asnoted above, movement of the engagement rod 520 is sensed by the sensor580 for the generation of a corresponding actuation request input (e.g.,input 382 of FIG. 3) to the controller 120. In response and since thevelocity control mode has been selected, the controller 120 generates anoperating command (e.g., command 390 of FIG. 3) that moves the steeringactuation devices (e.g., devices 142, 142′) at a rate of changecorresponding to a rate of change of the actuation request input (e.g.,input 370) on the joystick device 500.

Moreover, as discussed above, movement of the joystick grip interface530 results in corresponding movement within the velocity-based feedbackpack 560. In particular, pivoting of the joystick grip interface 530results in the pivoting of the pivot bracket 630 (e.g., via the pivotcollar 540 and engagement rod 520). As the pivot bracket 630 pivots, thefirst wall leg 654 of the U-shaped wall element 650 presses the firstspring leg 614 of the spring 610 in the pivoting direction on the otherside of the pivot axis 542 (e.g., to the right in FIG. 6B), while thefirst stop 672 maintains the position of the second spring leg 616 ofthe spring 610. This results in the spring 610 being placed undercompression, thereby generating a resistance force in the directionopposite to the pivoting direction. The resistance force is transferredthrough the pivot bracket 630, through the splined connection to theengagement rod 520, and through the collar 540 to the joystick gripinterface 530, such that the resistance force provides a feedback forceto the operator. Typically, the feedback force is consistent with thefeel of the joystick grip interface 530 in a velocity-based steeringcontrol strategy.

When operator pressure is no longer being applied to the joystick gripinterface 520, the force of the spring 610 at the first spring leg 614of the spring 610 presses the first wall leg 654 of the U-shaped wallelement 650 such that the pivot bracket 630 returns to the neutralposition. As a result, the engagement rod 520 rotates, which in turnpivots the joystick grip interface 530 back into the neutral position.

Referring briefly to FIG. 6C, a similar operation occurs in the oppositedirection when then joystick grip interface 530 is moved by the operatorin the right direction. Movement of the joystick grip interface 530 isinterpreted according to the velocity control mode and the spring 610imparts an appropriate feedback force. Subsequently, upon release, thespring 610 returns the pivot bracket 630 and thus the joystick gripinterface 530 back into the neutral position.

Accordingly, the configuration of the velocity-based feedback pack 560with the spring 610 provides haptic behavior is consistent with thevelocity-based steering control strategy. Elements other than the coilspring 610 may be provided, such as gas springs, air springs, or similarelements.

Reference is now made to FIGS. 7A-7C, which are cross-sectional views ofthe joystick device 500 through line 7-7 of FIG. 5A, particularlythrough the position-based feedback pack 570. In FIG. 7A, the joystickgrip interface 530 is in a neutral position; in FIG. 7B, the joystickgrip interface 530 has been moved leftward; and in FIG. 7C, the joystickgrip interface 530 has been moved rightward.

As shown, the position-based feedback pack 570 is a friction dampingpack and includes a position-maintaining, friction-based dampeningdevice formed by one or more fixed plates 710 and one or more pivotplates 720, each mounted on a housing 702. The plates 710, 720 may bearranged in a stacked and/or abutting configuration such that adjacentplanar surfaces of the plates 710, 720 abut against and frictionallyengage one another. Each plate 710, 720 defines a passageway 722 (one ofwhich is shown) respectively aligned with one another. The passageways722 through the pivot plates 720 includes a plurality of internallyextending teeth or splines 724, and the passageways (not shown) throughthe fixed plates 710 are larger than the passageways 722 through thepivot plates 720. As a result, the teeth 527 on the engagement rod 520are configured to engage the teeth 724 of the pivot plates 720 forrotational engagement, while the engagement rod 520 passes through thefixed plates 710 unencumbered.

Accordingly, when an operator desires to implement a steering functionin a position control mode, the operator rotates the knob 512 to aposition representing the position control mode. When the knob 512 isrotated into the position corresponding to the position control mode,the engagement rod 520 is translated by the rod 514 and cam 516. Uponmovement or repositioning of the engagement rod 520, the sensor 580determines the position of the engagement rod 520 and sends a controlmode selection input (e.g., input 380) to the controller 120, 120′, asdiscussed above. Upon the linear translation of the engagement rod 520into the position reflected by the knob 512 for the position controlmode, the teeth 527 at the end the end portion 526 of the engagement rod520 mesh with the teeth 724 of the pivot plates 720 of theposition-based feedback pack 570, as depicted in FIGS. 7A-7C.

Because the engagement rod 520 is engaged with the position-basedfeedback pack 570, the joystick device 500 behaves in anoperator-accustomed manner for position-based steering controlstrategies. As shown in FIG. 7A, in a neutral position, the joystickgrip interface 530 is positioned in a vertical orientation, although theneutral position may correspond to other angles relative to the groundplane in other embodiments.

Regardless of the position of the joystick grip interface 530, theplates 710, 720 abut one another and apply a mutual friction force toresist movement. When the joystick grip interface 530 is moved (e.g.,from neutral in FIG. 7A to the left as shown in FIG. 7B or to the rightas shown in FIG. 7C), the engagement rod 520 also pivots.

As noted above, movement of the engagement rod 520 is sensed by thesensor 580 for the generation of a corresponding actuation request input(e.g., input 382 of FIG. 3) to the controller 120. In response and sincethe position control mode has been selected, the controller 120generates an operating command (e.g., command 390 of FIG. 3) that thatmoves the steering actuation devices (e.g., devices 142, 142′) into aposition corresponding to a position of the actuation request input(e.g., input 370) on the joystick device 500.

Moreover, as discussed above, movement of the joystick grip interface530 results in corresponding movement within the position-based feedbackpack 570. In particular, pivoting of the joystick grip interface 530results in a force imparted on the pivot plates 720 via engagement ofthe engagement rod 520 and the pivot plates 720. When sufficient forceis placed on the joystick grip interface 530, the friction force betweenthe abutting plates 710, 720 is overcome and the pivot plates 720 moverelative to the fixed plates 710. The friction force from abuttingplates 710, 720 provides resistance as a feedback force for the operatorat the joystick grip interface 530 (e.g., through the engagement rod 520and collar 540). Typically, the feedback force is consistent with thefeel of the joystick grip interface 530 in a position-based steeringcontrol strategy. When operator pressure is no longer being applied tothe joystick grip interface 530, the friction force between abuttingplates 710, 720 maintains this position, and thus, the position of thejoystick grip interface 530.

In some examples, a detent arrangement 726 may be implemented to providea haptic indication of a center or neutral position. For example, adetent arrangement 726 may be cooperating detents on one or more of theplates 710, 720 such that a “click” or neutral position may be sensed bythe operator. Other mechanisms indicating the neutral position may beprovided, including spring arrangements, ball arrangements, and thelike.

Accordingly, the configuration of the position-based feedback pack 570with the friction plates 710, 720 provides haptic behavior is consistentwith the position-based steering control strategy. Position-maintainingelements other than the plates 710, 720 may be provided in otherembodiments.

Generally, the joystick device 400 of FIG. 4 may be considered an activesystem in which the motor (e.g., motor 430) generates the feedbackresponse, and the joystick device 500 of FIGS. 5A, 5B, 6A-6C, and 7A-7Cmay be considered a passive system in which passive elements (e.g., thespring 610 and plates 710, 720) generate the feedback response. However,in some embodiments, a joystick device may be provided as a semi-activesystem that includes characteristics of both active systems and passivesystems.

In one such semi-active embodiment, the joystick device may include apartial electro-mechanical joystick device with a positioning motor anda centering spring, each coupled to a joystick grip interface. Forexample, the positioning motor may be similar to the motor 430 describedabove with reference to FIG. 4 and the centering spring may be similarto the positioning spring 610 described above with reference FIGS. 5A,5B, and 6A-6C. As such, the positioning spring may be coupled to a pivotbracket that engages an engagement rod coupled to the joystick gripinterface, as described above, and the pivot bracket may further haveteeth that engage a drive shaft of a motor. As above, a steering modeselection switch may be provided to indicate the desired mode to thecontroller and the actuation request inputs from the joystick device areinterpreted accordingly.

Regarding application of a feedback force, typically in such anarrangement according to a velocity control mode, the motor is not usedand the device operates such as described above with the device of FIG.4 utilizing the feedback force of the coil spring. In effect, thepositioning motor may be locked in a center position. In the positioncontrol mode, the motor is actively controlled according toposition-based position control strategy such that a feedback force isapplied to the joystick grip interface through the pivot bracket orhousing. When the operator releases the joystick grip interface, themotor may maintain the position of the joystick grip interface.Moreover, the motor may be actively controlled to resist movement of thejoystick grip interface at too fast a speed that would overtax thesteering system, thereby providing a haptic feel to the operator thatthe joystick grip interface is being moved too fast.

Accordingly, the operator control system may selectively implement oneof two operator control strategies for steering a work vehicle, namely,a velocity-based steering control strategy and a position-based steeringcontrol strategy. In response to the operator selection that thevelocity-based steering control strategy is to be used, the joystickdevice acts in accordance with how the operator is accustomed to ajoystick device operating under the velocity-based steering controlstrategy and the work vehicle responds accordingly. In response to theoperator selection that the position-based steering control strategy isto be used, the joystick device acts in accordance with how the operatoris accustomed to a joystick device operating under the position-basedsteering control strategy and the work vehicle responds accordingly.

Also, the following examples are provided, which are numbered for easierreference:

1. A control system for a work vehicle having one or more actuationdevices, the control system comprising: an operator input deviceconfigured to receive operator input from an operator of the workvehicle; and a controller operatively connected to the operator inputdevice and to the one or more actuation devices, the controllerconfigured to: receive a control mode selection input including aposition control mode selection input or a velocity control modeselection input; receive an actuation request input from the operatorinput device; determine an operating command corresponding to theactuation request input from the operator input device according to thecontrol mode selection input; and issue the operating command to the oneor more actuation devices.

2. The control system of example 1, wherein, in the position controlmode, the operating command includes an instruction to move the one ormore actuation devices to a position corresponding to a positioncorresponding to the actuation request input from the operator inputdevice; and wherein, in the velocity control mode, the operating commandincludes an instruction to move the one or more actuation devices at arate of change corresponding to the position of the actuation requestinput from the operator input device.

3. The control system of example 1, wherein the operator input deviceincludes a grip interface having a range of motion for transmitting theoperator input to the operator input device.

4. The control system of example 3, wherein the operator input device isan electro-mechanical joystick device having a feedback motor coupled tothe grip interface; and wherein the controller is further configured to:determine a feedback command corresponding to movement of the gripinterface associated with the actuation request according to the controlmode selection input; and issue the feedback command to the feedbackmotor.

5. The control system of example 4, wherein, in the position controlmode, the feedback command includes an instruction to the feedback motorto maintain a position of the grip interface associated with at leastone of the actuation request input and the position of the one or moreactuation devices; and wherein, in the velocity control mode, thefeedback command includes an instruction to the feedback motor tore-center the grip interface following the actuation request input.

6. The control system of example 5, wherein, in the velocity controlmode, the feedback command includes an instruction to the feedback motorto provide a counteracting force resisting movement of the gripinterface that is less than or equal to a force required to move thegrip interface, wherein the counteracting force is linearly ornon-linearly proportional to the force required to move the gripinterface.

7. The control system of example 3, wherein the operator input device isa partial electro-mechanical joystick device having a positioning motorand a centering spring both coupled to the grip interface; wherein, inthe position control mode, the controller is further configured todetermine a position command corresponding to movement of the gripinterface associated with the actuation request input; and wherein, inthe velocity mode, the positioning motor is locked in a center position.

8. The control system of example 3, wherein the operator input device isa mechanical joystick having a position-maintaining device, a centeringdevice or both the position-maintaining device and the centering device;wherein the position-maintaining device is configured to maintain aposition of the grip interface after movement associated with theactuation request input; and wherein the centering device is configuredto center the grip interface after movement associated with theactuation request input.

9. The control system of example 8, wherein the position-maintainingdevice is a friction and damper device; and wherein the centering deviceis a centering spring.

10. The control system of example 10, wherein the operator input deviceincludes a selection switch; and further comprising: a sensor configuredto detect a position of the selection switch and provide the controlmode selection input to the controller.

11. The control system of example 10, wherein the operator input deviceincludes a link coupled to the selection switch and to either theposition-maintaining device or the centering device.

12. The control system of example 11, wherein the operator input deviceincludes both the position-maintaining device and the centering device;and wherein movement of the selection switch causes movement of the linkto selectively couple to either the position-maintaining device or thecentering device.

13. A control system for a work vehicle having one or more actuationdevices, the control system comprising: an operator input deviceconfigured to receive operator input from an operator of the workvehicle, wherein the operator input device includes a grip interfacehaving a range of motion for transmitting the operator input to theoperator input device; a controller operatively connected to theoperator input device and to the one or more actuation devices, thecontroller configured to: receive a control mode selection inputincluding a mode selection input as a position control mode or avelocity control mode; receive an actuation request input from theoperator input device; determine an operating command corresponding tothe actuation request input from the operator input device according tothe control mode selection input; and issue the operating command to theone or more actuation devices; wherein, in the position control mode,the operating command includes an instruction to move the one or moreactuation devices to a position corresponding to a positioncorresponding to the actuation request input from the operator inputdevice; and wherein, in the velocity control mode, the operating commandincludes an instruction to move the one or more actuation devices at arate of change corresponding to the position of the actuation requestinput from the operator input device.

14. The control system of example 13, wherein the operator input deviceis an electro-mechanical joystick having a feedback motor coupled to thegrip interface; and wherein the controller is further configured to:determine a feedback command corresponding to movement of the gripinterface associated with the actuation request input according to thecontrol mode selection input; and issue the feedback command to thefeedback motor, wherein, in the position control mode, the feedbackcommand includes an instruction to the feedback motor to maintain aposition of the grip interface associated with the actuation requestinput; and wherein, in the velocity control mode, the feedback commandincludes an instruction to the feedback motor to re-center the gripinterface following the actuation request input and to provide acounteracting force resisting movement of the grip interface that isless than a force required to move the grip interface, wherein thecounteracting force is linearly or non-linearly proportional to theforce required to move the grip interface.

15. The control system of example 13, wherein the operator input deviceincludes a mode selection switch; and wherein the control system furthercomprises a sensor configured to detect a position of the mode selectionswitch and provide the control mode selection input to the controller,wherein the operator input device is a mechanical joystick having afriction dampening device and a spring centering device; wherein thefriction dampening device is configured to maintain a position of thegrip interface after movement associated with the actuator request; andwherein the spring centering device is configured to center the gripinterface after movement associated with the actuator request, andwherein movement of the mode selection switch causes movement of thelink to selectively couple to either the position-maintaining device orthe centering device.

As used herein, unless otherwise limited or modified, lists withelements that are separated by conjunctive terms (e.g., “and”) and thatare also preceded by the phrase “one or more of” or “at least one of”indicate configurations or arrangements that potentially includeindividual elements of the list, or any combination thereof. Forexample, “at least one of A, B, and C” or “one or more of A, B, and C”indicates the possibilities of only A, only B, only C, or anycombination of two or more of A, B, and C (e.g., A and B; B and C; A andC; or A, B, and C).

As used herein, the term module refers to any hardware, software,firmware, electronic control component, processing logic, and/orprocessor device, individually or in any combination, including withoutlimitation: application specific integrated circuit (ASIC), anelectronic circuit, a processor (shared, dedicated, or group) and memorythat executes one or more software or firmware programs, a combinationallogic circuit, and/or other suitable components that provide thedescribed functionality.

Embodiments of the present disclosure may be described herein in termsof functional and/or logical block components and various processingsteps. It should be appreciated that such block components may berealized by any number of hardware, software, and/or firmware componentsconfigured to perform the specified functions. For example, anembodiment of the present disclosure may employ various integratedcircuit components, e.g., memory elements, digital signal processingelements, logic elements, look-up tables, or the like, which may carryout a variety of functions under the control of one or moremicroprocessors or other control devices. In addition, those skilled inthe art will appreciate that embodiments of the present disclosure maybe practiced in conjunction with any number of systems, and that theloader described herein is merely one example embodiment of the presentdisclosure.

For the sake of brevity, conventional techniques related to signalprocessing, data transmission, signaling, control, and other functionalaspects of the systems (and the individual operating components of thesystems) may not be described in detail herein. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent example functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in an embodiment of the present disclosure.

As will be appreciated by one skilled in the art, certain aspects of thedisclosed subject matter can be embodied as a method, system (e.g., awork vehicle control system included in a work vehicle), or computerprogram product. Accordingly, certain embodiments can be implementedentirely as hardware, entirely as software (including firmware, residentsoftware, micro-code, etc.) or as a combination of software and hardware(and other) aspects. Furthermore, certain embodiments can take the formof a computer program product on a computer-usable storage medium havingcomputer-usable program code embodied in the medium. Any suitablecomputer usable or computer readable storage or signal medium can beutilized.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The description of the present disclosure has been presented forpurposes of illustration and description, but is not intended to beexhaustive or limited to the disclosure in the form disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of thedisclosure. Explicitly referenced embodiments herein were chosen anddescribed in order to best explain the principles of the disclosure andtheir practical application, and to enable others of ordinary skill inthe art to understand the disclosure and recognize many alternatives,modifications, and variations on the described example(s). Accordingly,various embodiments and implementations other than those explicitlydescribed are within the scope of the following claims.

What is claimed is:
 1. A control system for a work vehicle having one ormore actuation devices, the control system comprising: an operator inputdevice configured to receive operator input from an operator of the workvehicle; and a controller operatively connected to the operator inputdevice and to the one or more actuation devices, the controllerconfigured to: receive a control mode selection input including aposition control mode selection input or a velocity control modeselection input; receive an actuation request input from the operatorinput device; determine an operating command corresponding to theactuation request input from the operator input device according to thecontrol mode selection input; and issue the operating command to the oneor more actuation devices.
 2. The control system of claim 1, wherein, inthe position control mode, the operating command includes an instructionto move the one or more actuation devices to a position corresponding toa position corresponding to the actuation request input from theoperator input device; and wherein, in the velocity control mode, theoperating command includes an instruction to move the one or moreactuation devices at a rate of change corresponding to the position ofthe actuation request input from the operator input device.
 3. Thecontrol system of claim 1, wherein the operator input device includes agrip interface having a range of motion for transmitting the operatorinput to the operator input device.
 4. The control system of claim 3,wherein the operator input device is an electro-mechanical joystickdevice having a feedback motor coupled to the grip interface; andwherein the controller is further configured to: determine a feedbackcommand corresponding to movement of the grip interface associated withthe actuation request according to the control mode selection input; andissue the feedback command to the feedback motor.
 5. The control systemof claim 4, wherein, in the position control mode, the feedback commandincludes an instruction to the feedback motor to maintain a position ofthe grip interface associated with at least one of the actuation requestinput and the position of the one or more actuation devices; andwherein, in the velocity control mode, the feedback command includes aninstruction to the feedback motor to re-center the grip interfacefollowing the actuation request input.
 6. The control system of claim 5,wherein, in the velocity control mode, the feedback command includes aninstruction to the feedback motor to provide a counteracting forceresisting movement of the grip interface that is less than or equal to aforce required to move the grip interface.
 7. The control system ofclaim 6, wherein the counteracting force is linearly or non-linearlyproportional to the force required to move the grip interface.
 8. Thecontrol system of claim 3, wherein the operator input device is apartial electro-mechanical joystick device having a positioning motorand a centering spring both coupled to the grip interface; wherein, inthe position control mode, the controller is further configured todetermine a position command corresponding to movement of the gripinterface associated with the actuation request input; and wherein, inthe velocity mode, the positioning motor is locked in a center position.9. The control system of claim 3, wherein the operator input device is amechanical joystick having a position-maintaining device, a centeringdevice or both the position-maintaining device and the centering device;wherein the position-maintaining device is configured to maintain aposition of the grip interface after movement associated with theactuation request input; and wherein the centering device is configuredto center the grip interface after movement associated with theactuation request input.
 10. The control system of claim 9, wherein theposition-maintaining device is a friction and damper device; and whereinthe centering device is a centering spring.
 11. The control system ofclaim 9, wherein the operator input device includes a selection switch;and further comprising: a sensor configured to detect a position of theselection switch and provide the control mode selection input to thecontroller.
 12. The control system of claim 11, wherein the operatorinput device includes a link coupled to the selection switch and toeither the position-maintaining device or the centering device.
 13. Thecontrol system of claim 12, wherein the operator input device includesboth the position-maintaining device and the centering device; andwherein movement of the selection switch causes movement of the link toselectively couple to either the position-maintaining device or thecentering device.
 14. A control system for a work vehicle having one ormore actuation devices, the control system comprising: an operator inputdevice configured to receive operator input from an operator of the workvehicle; a controller operatively connected to the operator input deviceand to the one or more actuation devices, the controller configured to:receive a control mode selection input including a mode selection inputas a position control mode or a velocity control mode; receive anactuation request input from the operator input device; determine anoperating command corresponding to the actuation request input from theoperator input device according to the control mode selection input; andissue the operating command to the one or more actuation devices;wherein, in the position control mode, the operating command includes aninstruction to move the one or more actuation devices to a positioncorresponding to a position corresponding to the actuation request inputfrom the operator input device; and wherein, in the velocity controlmode, the operating command includes an instruction to move the one ormore actuation devices at a rate of change corresponding to the positionof the actuation request input from the operator input device.
 15. Thecontrol system of claim 14, wherein the operator input device includes agrip interface having a range of motion for transmitting the operatorinput to the operator input device.
 16. The control system of claim 15,wherein the operator input device is an electro-mechanical joystickhaving a feedback motor coupled to the grip interface; and wherein thecontroller is further configured to: determine a feedback commandcorresponding to movement of the grip interface associated with theactuation request input according to the control mode selection input;and issue the feedback command to the feedback motor, wherein, in theposition control mode, the feedback command includes an instruction tothe feedback motor to maintain a position of the grip interfaceassociated with at least one of the actuation request input and theposition of the one or more actuation devices; and wherein, in thevelocity control mode, the feedback command includes an instruction tothe feedback motor to re-center the grip interface following theactuation request input.
 17. The control system of claim 16, wherein, inthe velocity control mode, the feedback command includes an instructionto the feedback motor to provide a counteracting force resistingmovement of the grip interface that is less than or equal to a forcerequired to move the grip interface; and wherein the counteracting forceis linearly or non-linearly proportional to the force required to movethe grip interface.
 18. The control system of claim 15, wherein theoperator input device is a mechanical joystick having a frictiondampening device, a spring centering device or both the frictiondampening device and the spring centering device; wherein the frictiondampening device is configured to maintain a position of the gripinterface after movement associated with the actuator request; andwherein the spring centering device is configured to center the gripinterface after movement associated with the actuator request.
 19. Thecontrol system of claim 18, wherein the operator input device includes amode selection switch; and further comprising: a sensor configured todetect a position of the mode selection switch and provide the controlmode selection input to the controller.
 20. The control system of claim19, wherein the operator input device includes both theposition-maintaining device and the centering device; and whereinmovement of the mode selection switch causes movement of the link toselectively couple to either the position-maintaining device or thecentering device.